This project is an investigation of gonadal hormone influences on human sexually-dimorphic cognitive and social behavior. It is a continuation of an earlier study, which demonstrated hormonal influences on childhood play behavior and activities, and represents the first longitudinal study of the behavioral consequences of elevated prenatal androgen exposure. The purpose of the proposed study is to elaborate the behavioral mechanisms through which gonadal hormones masculinize behavior, and the developmental relationships among the various hormonally influenced behaviors. The aims are tow-fold: (1) to follow-up hormone-exposed and control children already tested on early play behavior (a) to see if these hormone-exposed girls also have enhanced spatial ability, and, if so, (b) to determine whether hormonal influences on spatial ability are the result of increased play with boys' toys; (2) to study in detail, using aggregate measures, other sex-typed behaviors (activity level, sex-role self- concept, nurturance) in these children (a) to determine whether these behaviors are also influenced by prenatal androgen, and, if so, (b) to assess if increased motor activity level accounts for participation in masculine activities. Subjects include 140 boys and girl aged 2-11: 70 patients with congenital adrenal hyperplasia (CAH), a genetic disease which results in increased prenatal levels of androgen, and 70 sex- and age-matched siblings or cousins who serve as controls. Subjects will be tested on two occasions on toy preference, rough-and-tumble play, activity level, nurturance, sex-role self-concept, and cognitive abilities. All behaviors will be assessed with multiple measures to obtain stable, reliable individual differences on the traits of interest. The main hypotheses are that: (a) hormonal influences on toy preferences are mediated by hormonal influences on activity level, i.e., elevated prenatal androgens produce increased motor activity, which leads to CAH girls playing with boys' toys, because these toys allow for active play; and (b) hormonal influences on early toy preference only partially mediate hormonal influences on later spatial ability, i.e., CAH girls' preference for boys' toys facilitates the development of later spatial ability, but this ability is also influenced directly by gonadal hormones. Results from this study will provide information about hormonal influences on the development of specific behaviors that are both socially and educationally relevant. They will also provide information that can be used in the medical management and counseling of patients with CAH.